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MP159 Screws

MP159 Screws As aerospace engineering advances, so must the materials to meet the technological requirements of this industry. Screws made from MP159 have been developed to provide a solution to high temperature, high strength components. MP159 Screws offer strength capabilities similar to other Cobalt Alloys (MP35N) but can be used at much higher temperatures - up to 1100°F, compared to MP35N’s usable limit of 800F. In addition, MP159, can be used beyond 1100°F in short term situations.

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Ultra-strength combined with extreme temperature capabilities
Extreme high strength properties up to 275 ksi ultimate tensile.
Maintains superior strength to 1100°F.

Key Benefits

High ultimate tensile strength of 275 ksi and yield strength of 265 ksi (Cold Worked and Age Hardened) combined with excellent ductility and toughness
Similar corrosion resistance compared to MP35N which is usable in mineral acids, hydrogen sulfide, seawater and salt spray environments.
Excellent fatigue resistance and creep strength at elevated temperatures.
Excellent resistance to crevice corrosion, stress corrosion cracking and hydrogen embrittlement.

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RAYCHIN LIMITED

Name: MP159 Screws
SKU: 0

MP159 Screws · Socket Head / Hex Head / Pan Head / Flat Head / Set Screws · Inch & Metric

MP159 Screws: Ultra-High Strength Cobalt-Nickel Alloy Screws for Extreme Temperature Applications

MP159 (UNS R30159) | AMS 5841 / 5842 / 5843 | Co-Ni-Cr-Mo Multiphase Alloy

RAYCHIN LIMITED is a leading manufacturer of MP159 Screws – precision threaded fasteners engineered from cobalt-nickel-chromium-molybdenum multiphase superalloy, delivering the ultimate combination of ultra-high strength, exceptional corrosion resistance, and reliable performance in the most demanding high-temperature bolted joints. Our comprehensive screw product line includes socket head cap screws, hex head screws, pan head screws, flat head screws, button head screws, and set screws – all manufactured to the highest precision standards. Through precise cold working (48% reduction) and age hardening, MP159 achieves ultimate tensile strength up to 275 ksi (1895 MPa) while maintaining excellent ductility and toughness. Developed specifically for higher operating temperatures, MP159 can perform in applications up to 593°C (1100°F), surpassing the capabilities of MP35N by 300°F. Our portfolio includes all standard and custom configurations manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards, including ASME B18.3 (inch series), ISO 4762 (socket head), ISO 4014 (hex head), and DIN 912. Whether you require MP159 socket head cap screws for advanced gas turbine engines, MP159 hex head screws for downhole drilling tools, or MP159 set screws for medical devices, RAYCHIN delivers precision, quality, and full traceability. All mechanical properties are presented in MPa and ksi (kilopound per square inch).

MP159 screwsMP159 socket head cap screwsMP159 hex head screwsMP159 pan head screwsMP159 flat head screwsMP159 button head screwsMP159 set screwsMP159 machine screwsUNS R30159 screwsAMS 5841 screwsAMS 5842 screwsAMS 5843 screwscobalt nickel alloy screwsultra high strength screwsnon-magnetic screwsaerospace screwsjet engine fastenershigh temperature screwsgas turbine fastenersDIN 912 MP159ISO 4762 MP159

MP159 Screws – Design & Configurations

Socket Head Cap Screws

MP159 socket head cap screws feature a cylindrical head with internal hex drive, providing high tightening torque and clean appearance. Manufactured to ASME B18.3 (inch) and ISO 4762 (metric). Available with standard or reduced head heights. Precision-formed sockets ensure consistent engagement. Ideal for confined spaces and high-strength assemblies in turbine engines and aerospace structures.

Hex Head Screws

MP159 hex head screws (hex cap screws) are designed for heavy-duty bolting applications requiring high clamping forces. Manufactured to ASME B18.2.1 (inch) and ISO 4014 / ISO 4017 (metric). Full range of diameters from #0 to 2" (M1.6 to M48). Precision forged heads and rolled threads for maximum strength. Used extensively in landing gear assemblies and downhole tools.

Pan Head / Machine Screws

MP159 pan head screws and machine screws are used in electronic enclosures, instrument panels, and light structural applications. Drives include Phillips, slotted, and internal hex. Manufactured to ASME B18.6.3 (inch) and ISO 1580 / ISO 7045 (metric). Smooth dome head provides finished appearance and reduces snag points.

Flat Head Countersunk Screws

MP159 flat head screws (countersunk) feature a conical bearing surface and flat top for flush installation. Available with 82° (inch), 100° (aerospace), and 90° (metric) countersink angles. Ideal for aerodynamic surfaces, confined spaces, and applications requiring smooth profiles. Manufactured to ASME B18.3 (inch) and ISO 10642 (metric).

Button Head Cap Screws

MP159 button head screws combine low-profile rounded head with internal hex drive, providing wide bearing surface for clamping thin materials. Head dimensions conform to ASME B18.3 (inch) and ISO 7380 (metric). Low head profile prevents interference with moving parts and reduces snag points in assemblies.

Set Screws (Grub Screws)

MP159 set screws (grub screws) are headless fasteners with various point styles: cup point, cone point, flat point, and dog point. Used to secure rotating components such as gears and pulleys onto shafts. Available with hex socket or slotted drive. Manufactured to ASME B18.3 (inch) and ISO 4026-4029 (metric). Exceptional resistance to loosening under vibration.

Thread Specifications

MP159 screws available with Unified Coarse (UNC), Unified Fine (UNF), UNJF-3A (aerospace), and metric coarse/fine threads. Thread classes 2A, 3A, 6g. Sizes from #0 to 1" (M1.6 to M24) for most head styles, with hex head available up to 2" (M48). Precision rolled threads for superior fatigue life. Full thread or partial thread options available.

Aerospace & Military Standards

Our MP159 screws meet applicable sections of NAS1351/1352 (socket head), NAS1802 (hex head), NASM 8830, MS16995, MS20073-20083, and AN42-AN73. Full compliance with AMS 5841 (solution treated), AMS 5842 (work strengthened), and AMS 5843 (full condition - cold worked and aged) for material and heat treatment. GE Aviation and Pratt & Whitney approved for engine fastener applications.

Custom & Non-Standard Screws

Need a special head configuration, proprietary drive, non-standard length, or unique thread form? RAYCHIN engineers design and produce custom MP159 screws to your exact specifications – any condition (annealed, cold worked, aged), with full material traceability. Prototype to production volumes supported.

Critical Applications of MP159 Screws

Aerospace & Defense

MP159 screws are extensively used in advanced gas turbine engines, jet propulsion systems, rocket boosters, landing gear assemblies, and airframe structural joints. The alloy's exceptional high-temperature strength (up to 1100°F) ensures reliable performance in turbine sections, while maintaining excellent fatigue resistance under cyclic loading. Non-magnetic properties essential for sensitive instrumentation. GE Aviation specifies MP159 for CF6 and CFM56 engine applications.

Oil & Gas / Downhole Tools

MP159 screws qualified per NACE MR0175 for downhole drilling tools, MWD/LWD equipment, wellhead connectors, BOP stacks, and subsea trees. Resist sulfide stress cracking (SSC) and pitting in H₂S/CO₂ environments at elevated pressures and temperatures. Socket head and hex head designs allow high preload in confined tool joints while maintaining exceptional resistance to hydrogen embrittlement.

Power Generation

MP159 screws in gas turbines, steam turbines, and nuclear reactor internals provide reliable fastening of casing bolts, sensor mounts, and control linkages. Maintain clamping force after thousands of thermal cycles from cryogenic to 1100°F without relaxation. Excellent creep strength (>1000 hours at 650°C/300 MPa) and fatigue resistance at elevated temperatures ensure long-term reliability.

Medical & Surgical Implants

MP159 screws used in surgical instruments, orthopedic external fixators, prosthetic devices, bone plates, and dental implants. Full biocompatibility, excellent fatigue resistance for long-term cyclic loading, and non-magnetic for MRI compatibility. Precision head styles allow accurate torque control during surgical procedures. Used in prosthetic devices requiring exceptional strength and corrosion resistance in body fluids.

Marine & Subsea

MP159 screws in seawater pump flanges, subsea connector assemblies, ROV systems, and offshore platform components resist pitting and crevice corrosion in saltwater. Virtually immune to crevice corrosion, stress corrosion cracking, and pitting even at the highest strength levels. Hex head and socket head designs are ideal for marine environments where debris could clog socket drives.

Chemical Processing

MP159 screws in high-pressure reactor flanges, pump casings, and valve bonnets resist most mineral acids, hydrogen sulfide, and chloride solutions. Excellent resistance to oxidizing and reducing atmospheres, making them ideal for chemical processing equipment and pulp & paper machinery. Superior resistance to stress corrosion cracking in aggressive chemical environments.

International Standards & Global Designations – MP159 Screws

RAYCHIN LIMITED manufactures MP159 screws from vacuum induction melted (VIM) and vacuum arc remelted (VAR) material conforming to the most widely used national and international specifications. All material is traceable to the mill.

Designation	Standard / Specification	Description
UNS R30159	Unified Numbering System	Standard designation for MP159 alloy chemistry
AMS 5841	Aerospace Material Specification	Bar, rod, wire; solution heat treated (1040-1055°C, 4-8h, water quench)
AMS 5842	Aerospace Material Specification	Solution heat treated and work strengthened (cold worked)
AMS 5843	Aerospace Material Specification	Solution heat treated, work strengthened, and aged – full condition for maximum strength
GH159 / GH6159	Chinese Standard	Chinese designation for MP159 alloy (Q/6S 992, C3S 284)
GE S-400 / S1000	GE Aviation Specification	Engine fasteners material approval
PWA LCS	Pratt & Whitney Specification	Material approval for aerospace applications
RR SABRe Edition 2	Rolls-Royce Specification	Material approval for aerospace applications
ASME B18.3	American Society of Mechanical Engineers	Socket head cap screws (inch series)
ASME B18.2.1	American Society of Mechanical Engineers	Hex head screws (inch series)
ISO 4762	International Organization for Standardization	Hexagon socket head cap screws (metric)
ISO 4014 / 4017	International Organization for Standardization	Hex head screws (metric series)
DIN 912 / DIN 933	Deutsches Institut für Normung	Socket head and hex head screws (metric series)
NAS1351/1352	National Aerospace Standards	Aerospace socket head screws

UNS R30159 AMS 5841 AMS 5842 AMS 5843 GH159 GE S-400 PWA LCS ASME B18.3 ISO 4762 DIN 912

Chemical Composition (Weight %) – MP159 Alloy for Screws

Our MP159 screws are produced from vacuum induction melted (VIM) and vacuum arc remelted (VAR) material conforming to the following limits per AMS and industry standards.

Element	Min %	Max %	Typical
Cobalt (Co)	34.0	38.0	35.7
Nickel (Ni)	24.0	27.0	25.5
Chromium (Cr)	18.0	20.0	19.0
Iron (Fe)	8.0	10.0	9.0
Molybdenum (Mo)	6.0	8.0	7.0
Titanium (Ti)	2.5	3.3	3.0
Niobium (Nb)	0.25	0.75	0.6
Aluminum (Al)	0.10	0.30	0.2
Carbon (C)	—	0.04	<0.03
Manganese (Mn)	—	0.20	<0.10
Silicon (Si)	—	0.20	<0.10
Sulfur (S)	—	0.010	<0.005
Phosphorus (P)	—	0.010	<0.008
Boron (B)	—	0.03	<0.03

Metallurgical note: MP159 is a multiphase cobalt-nickel-chromium-molybdenum alloy strengthened through a unique combination of solid solution strengthening, cold work hardening (typically 48% reduction), and age hardening via precipitation of γ' phase [Ni₃(Al, Ti, Nb)] and ε phase formation. The alloy maintains excellent ductility even at high cold reduction levels, enabling production of high-strength screws with precision-formed heads and rolled threads. It remains essentially non-magnetic (permeability ~1.00265) even after extensive cold working, critical for medical and directional drilling applications. MP159 was developed specifically for higher operating temperatures compared to MP35N, with service capability up to 1100°F (593°C). Heat treatment per AMS 5843: solution anneal 1040-1055°C (1900-1925°F), 48% cold work, age 650-675°C (1200-1250°F) for 4-4.5 hours. The high chromium (19%) and molybdenum (7%) content promotes formation of a dense Cr₂O₃ protective film, providing exceptional hot corrosion resistance. Long rod-like γ' phases provide outward diffusion channels for Cr, accelerating formation of protective oxide layers.

Complete Mechanical & Physical Properties – MP159 Screws (MPa / ksi)

MP159 screws are supplied in various conditions per AMS specifications. Data represent typical values based on AMS and industry standards. ksi values (kilopound per square inch) are provided alongside MPa.

Mechanical Properties by Condition – MP159 Screws

Condition / Specification	Tensile Strength (MPa)	Tensile Strength (ksi)	Yield Strength 0.2% (MPa)	Yield Strength 0.2% (ksi)	Elongation (%)	Hardness
Annealed / Solution Treated (AMS 5841)	848	123	400	58	60	20 HRC max
Solution Treated + Work Strengthened (48% cold work, AMS 5842)	1585	230	1413	205	12	≥38 HRC
Cold Worked + Aged (AMS 5843) – Full Condition	1895 (min 1790)	275 (min 260)	1827 (min 1725)	265 (min 250)	8 (min 6)	≥44 HRC
Typical Maximum (Aged)	2070	300	1790	260	8-10	45-50 HRC
650°C High Temperature Strength	≥1000	≥145	≥700	≥101	—	—
Creep Rupture Life (650°C/300 MPa)	>1000 hours		Superior creep resistance

Physical Properties – MP159 Alloy

Property	Metric	Imperial	Notes
Density	8.33 g/cm³	0.301 lb/in³
Melting Range	1315-1427°C	2400-2600°F
Elastic Modulus (E) at 20°C	210-220 GPa	30.5-32.0 x 10³ ksi
Elastic Modulus at 232°C (450°F)	208 GPa	30200 ksi	Annealed condition
Shear Modulus (G) at 232°C	75.8 GPa	11000 ksi	Annealed condition
Poisson's Ratio	0.31	0.31
Thermal Expansion (20-600°C)	14.9 µm/m°C	8.28 µin/in°F
Thermal Conductivity at 600°C	20.5 W/m·K	142 Btu·in/(hr·ft²·°F)	Cold worked + aged
Electrical Resistivity	1.096 µΩ·m	43.1 µΩ·in	At 25°C, aged condition
Magnetic Permeability	~1.00265	~1.00265	Essentially non-magnetic

High‑Temperature Performance of MP159 Screws

MP159 alloy was developed specifically to meet the need for a fastener alloy that could perform under the higher operating temperatures required for turbine engines and other high performance motors. It has advantages similar to MP35N but can perform in applications up to 593°C (1100°F) and is suitable for short term use at even higher temperatures (up to 649°C/1200°F). The high chromium content (19%) promotes formation of a dense, protective Cr₂O₃ film that provides excellent hot corrosion resistance in aggressive environments.

Elevated Temperature Capabilities

Property	Value	Notes
Maximum Service Temperature (continuous)	593°C (1100°F)	In fully work hardened and aged condition
Short Term Use Temperature	649°C (1200°F)	Suitable for short term use at higher temperatures
650°C Strength	Tensile ≥1000 MPa	Excellent retention of mechanical properties
Creep Resistance	>1000 hours @ 650°C/300 MPa	Superior creep rupture life
Oxidation Resistance (900°C)	<0.1 mm/year	Excellent high-temperature oxidation resistance
Hot Corrosion Resistance	Superior at 800°C	Forms dense Cr₂O₃ protective film
Operating Temperature Range	-253°C to 593°C (-423°F to 1100°F)	Full operating temperature range

High-Temperature Comparison – MP159 vs. MP35N

Alloy	Maximum Service Temperature	Typical Application
MP159	1100°F (593°C)	Turbine engine fasteners, high-temperature screws
MP35N	800°F (427°C)	General purpose high-strength fasteners
Inconel 718	1300°F (704°C)	Higher temperature capability, lower strength than MP159 at moderate temps

Note: MP159 fills the critical gap between MP35N and higher-temperature alloys like Inconel 718, offering superior strength up to 1100°F with excellent corrosion resistance. Recent research demonstrates that cryo-rolled MP159 with long rod-like γ′ phases exhibits enhanced hot corrosion resistance due to accelerated Cr diffusion and formation of protective Cr₂O₃ films.

Exceptional Corrosion Resistance of MP159 Screws

MP159 alloy offers outstanding corrosion resistance across a wide range of aggressive environments, making it suitable for the most demanding applications including medical implants, downhole tools, marine equipment, and chemical processing.

General Corrosion Resistance: Similar corrosion resistance to MP35N, excellent resistance to most mineral acids, hydrogen sulfide, seawater and salt spray environments.
Stress Corrosion Cracking (SCC): Exceptional resistance to chloride and sour (H₂S) environments. Qualified per NACE MR0175 for oil & gas applications.
Pitting and Crevice Corrosion: Superior resistance to localized corrosion in seawater and brine solutions due to high chromium (19%) and molybdenum (7%) content. Virtually immune to crevice corrosion and pitting even at the highest strength levels.
Hydrogen Embrittlement: Excellent resistance to hydrogen embrittlement when properly heat treated.
Hot Corrosion Resistance: Superior hot corrosion resistance at elevated temperatures due to formation of dense Cr₂O₃ protective film, promoted by high Cr content and the presence of Nb. Long rod-like γ' phases provide outward diffusion channels for Cr, accelerating formation of protective oxide layers.
Oxidation Resistance: In 900°C air, oxidation rate <0.1 mm/year, superior to many competing alloys.
Seawater Performance: In seawater, MP159 is virtually immune to crevice corrosion, stress corrosion cracking, and pitting.
Biocompatibility: Fully biocompatible for medical implant applications.
Bimetallic Corrosion: Can be safely connected to stainless steels, titanium alloys, and other corrosion-resistant alloys with appropriate precautions.

Manufacturing Standards – MP159 Screws

All MP159 screws are manufactured and tested to meet the following standards:

AMS 5841AMS 5842AMS 5843ASTM F562NACE MR0175NACE MR0103API 20FASME B18.3ASME B18.2.1ISO 4762ISO 4014DIN 912NAS1351/1352GE S-400PWA LCSEN 10204 3.1/3.2

We offer surface finishes: passivation (ASTM A967), silver plating (AMS 2410 for anti‑seize), PTFE coating, electropolish. Full traceability and destructive/non‑destructive testing available (UT, MPI, PMI). ISO 13485 certified for medical applications with cleanroom packaging available.

Why RAYCHIN LIMITED – The MP159 Screw Authority

Metallurgical expertise: Decades of experience with cobalt‑nickel superalloys. We ensure precise heat treatment: solution anneal (1040-1055°C), controlled cold work (48% reduction), and aging (650-675°C) per AMS 5843 schedules. In‑house PMI verifies chemistry of every heat. Our MP159 screws achieve 260-300 ksi ultimate tensile strength with full traceability.

Global certifications: ISO 9001, AS9100D, ISO 13485 (medical), PED, API Q1, NADCAP accredited processes. All screws supplied with EN 10204 3.1/3.2 certifications, NACE compliance when required.

Precision heading & thread rolling: CNC cold heading and precision thread rolling ensure accurate head geometry and thread form per ASME, ISO, and DIN standards. Class 2A/3A/6g thread fit. 100% inspection available. Straightness and dimensional tolerances held to the tightest specifications.

Custom solutions: Special head configurations, proprietary drives, non‑standard lengths, tailored packaging. In-house metallurgical laboratory and failure analysis capabilities.

Contact the MP159 screw experts

Request a quotation for MP159 socket head cap screws, hex head screws, pan head screws, flat head screws, set screws – any standard (ASME, ISO, DIN, NAS) – any condition (AMS 5841, 5842, 5843), any quantity. Global delivery. Mechanical data in MPa/ksi available for all products.

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